The primary function of this group has been to apply the principles of pharmacokinetics to questions of relevance to the clinical oncology service. Studies completed or active include: 1. Intraperitoneal 5FU as adjuvant treatment for colon carcinoma - Surgery Branch. 2. Halogenated pyrimidine radiosensitizers - Radiation Oncology Branch. 3. Intraventricular chemotherapy - Pediatric Branch. 4. Phase I trials of new agents (Tiazofuran, Carboplatinum, Dihydroazacytidine) - Medicine Branch. 5. Pharmacokinetic evaluation of established agents - Adriamycin, 6-mercaptopurine, cisplatin - Medicine and Pediatric Branches. In addition to direct clinical pharmacokinetic projects, this group has ongoing projects on the relationship between preclinical and human pharmacokinetic studies. Both experimental studies (rodents) and theoretical aspects. More detailed pharmacokinetic modeling has been jointly developed in collaboration with the Biomedical Engineering and Instrumentation Branch, DRS/NIH. Pharmacokinetic consultation is also provided to the Surgical Neurology Branch, NINCDS, for the treatment of CNS neoplasms.